Process for the production of neopentylglycol-carboxylic acid-carbonic acid mixed esters

ABSTRACT

Process for producing neopentylglycol-carboxylic acid-carbonic acid mixed esters by transesterifying a diaryl carbonate with a neopentylglycol-carboxylic acid semiester at a temperature of from about 180* to about 220* C. and the utility of such products in the production of lacquers and resins and plastics.

United States Patent [72] Inventor Erwin Muller Leverkusen, Germany [21]App]. No. 732,512

[22] Filed May 28, 1968 [45] Patented Nov. 23, 197 l [73] AssigneeFarbeniabriken Bayer Aktiengesellschait Leverkusen, Germany [32]Priority July I2, 1967 [33] Germany [54] PROCESS FOR THE PRODUCTION OFNEOPENTYLGLYCOL-CARBOXYLIC ACID- CARBONIC ACID MIXED ESTERS 5 Claims, NoDrawings [52] US. Cl 260/463, 260/l6. 260/22 R, 260/75 R, 260/86l 51 lm.Cl ..C07c 69/00, C08g l7/l3,CO8g 17/18 501 Fieldoi'Sear-ch ..260/463,75R,77.5 D,77,4l0,6

[56] References Cited UNITED STATES PATENTS 3,207,814 9/1965 GoldbergPrimary E.raminerElbert L. Roberts Assislan! Exan|iner Diana G. RiversAtl0rneyConnolly and Hutz PROCESS FOR THE PRODUCTION OFNEOPENTYLGLYCOL-CARBOXYLIC ACID-CARBONIC ACID MIXED ESTERS The presentinvention relates to a process for the production ofneopentylglycol-carboxylic acid-carbonic acid mixed esters, which offersparticular technical advantages.

lt is known that diaryl carbonates, for example, diphenyl carbonate, caneasily be transesterified with alcohols with the elimination of thecorresponding phenol and with the formation of corresponding alkylcarbonates. If glycols are reacted with diaryl carbonates, the use oflong-chain glycols with at least five chain members yields low-,medium-, or highmolecular straight-chain glycol carbonates orpolycarbonates in accordance with the molar ratios applied, whereas theuse of short-chain glycols with up to four chain members, such asethylene-glycol, l,2- and 1,3-propylene-glycol, neopentylglycol and1,4-butane-diol yields the cyclic carbonates. The tendency to form suchcyclic carbonates is so strong that it prevails even in the reaction ofdiaryl carbonates with esterified short-chain glycols in that a twofoldtransesterification takes place in this case, with the formation of thecorresponding carboxylic acid aryl ester besides the cyclic carbonate.That is to say that, by heating, for example, ethylene glycol-benzoicacid monoor diesters with diphenyl carbonate in a molar ratio of 1:l,there is obtained 1 mole of cyclic ethylene carbonate and 1 mole ofbenzoic acid phenyl ester and phenol or 2 moles benzoic acid phenylester. The reaction of, for example, 1,2-propylene-glycolor1,4-butane-diol-carboxylic acid esters leads to corresponding results.

Although, as a rule, branched short-chain bifunctional compounds formcyclic derivatives with particular ease, it has been found,surprisingly, that in the case where neopentylglycol-carboxylic acidesters are heated with diaryl carbonates, the twofoldtransesterification does not take place, i.e. with the use ofneopentylglycol-carboxylic acid diesters, a reaction with diarylcarbonate in the temperature range from about 180 to about 220 C.,whereas the use of neopentylglycol-carboxylic acid semiesters leads tothe formation of the corresponding neopentylglycol-carboxylicacid-carbonic acid mixed esters. The present invention for theproduction of neopentylglycol-carboxylic acid-carbonic acid mixed estersutilizes this observation.

The object of the invention thus comprises a process for the productionof neopentylglycol-carboxylic acid-carbonic acid mixed esters, whichcomprises transesterifying a diaryl carbonate with aneopentylglycol-carboxylic acid semiester, optionally in admixture withmonohydric alcohols or/and with glycols having at least five chainmembers, in the temperature range from about 180 to about 220 C., thecorresponding phenol being distilled off.

Depending on whether neopentylglycol-monocarboxylic acid semiesters or-dicarboxylic acid di-semiesters are used as starting materials and onthe proportion in which dicarboxylic acid semiesters and diarylcarbonate are reacted, optionally with the addition of monohydricalcohols or/and long-chain glycols, there are obtained monomeric,oligomeric or polymeric neopentylglycol-carboxylic acid-carbonic acidmixed esters.

Neopentylglycol-monocarboxylic acid semiesters which are suitable forthe process are the semiesters of, for example, acetic acid, propionicacid, butyric acid, isobutyric acid, valerianic acid and of higherstraight-chain or branched fatty acids as well as of unsaturated or/andsubstituted carboxylic acids, such as mono-, diand trichloroacetic acid,phenylacetic acid, acrylic and methacrylic acid, crotonic acid, oleicacid, linseed oil fatty acid and cinnamic acid, further of aromaticacids, such as benzoic acid, chlorobenzoic acids, nitrobenzoic acids,toluylic acid and anisic acid.

Examples of suitable dicarboxylic acid di-semiesters are the semiestersof the following dicarboxylic acids: malonic, succinic, glutaric,adipid, pimelic, suberic, sebacic, maleic, fumaric, citraconic,mesaconic, dihydromuconic, tetrahydrophthalic,endomethylene-tetrahydrophthalic acid, phthalic acids and chlorophthalicacids.

' A part from monomeric neopentylglycol-dicarboxylic acid di-semiesters,homoor heteropolyesters with neopentylglycol-dicarboxylic acid semiesterend groups can also be used as starting material, for example,neopentylglycol-adipic or phthalic acid polyesters with neopentylglycolsemiester end groups or similar polyesters with radicals of variousdicarboxylic acids.

Suitable diaryl carbonates, besides diphenyl carbonate, are, forexample, dicresyl carbonates and bischlorophenyl carbonates.

Monohydric alcohols which may be added are, for example, octyl alcohol,nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol andoctadecyl alcohol.

Long-chain glycols which may be added are, for example, diandpolyethylene and propyleneglycols, pentamethylene, hexamethylene,heptamethylene, and octamethylene glycol, p-phenylene-di-p-hydroxyethylether and 4,4'-di-(p-hydroxyethoxy)-diphenyl-dimethyl-methane, as wellas polyethers with terminal hydroxyl groups or polyesters with semiesterend groups of long-chain glycols.

The reaction may be carried out under reduce pressure, in,

order to facilitate the distilling off of the eliminated phenol.

Depending upon their composition, the products of the process areliquids of low to high viscosity or resinous substances. They can beused as plasticizers for lacquer raw materials and synthetic materialssuch as polyvinyl chloride or as intermediates for the production ofhigher or high molecular products, the higher or high molecular productsas lacquer raw materials or synthetic resins. lf the products containreactive double bonds, for example, the radicals of unsaturateddicarboxylic acids, they can be polymerized or copolymerized with otherpolymerizable materials and thus be converted into synthetic resins orplastics.

EXAMPLE 1 A mixture of 208 g.(l mole) neopentylglycol-benzoic acidsemiester and 107 g. (0.5 mole) diphenyl carbonate is gradually heatedto 220 C. on a descending cooler with stirring and the passing over ofnitrogen, until phenol no longer distills over (distilling temperature180 C.). A gradually increasing vacuum is then applied and the residualamounts of phenol are withdrawn at 200 C./l2 mm.Hg. ln all, 95 g. phenol(calculated 94 g.) are distilled off. The remaining mixed ester, 215 g.(theory 221 g.), is a viscous oil.

EXAMPLE 2 A mixture of 1290 g. (3.8 moles) terephthalicacid-bisneopentylglycol ester and 750 g. (3.5 moles) diphenyl carbonateis treated under the conditions described in example 1. There areobtained 657 g. (calculated 660 g.) phenol. The remaining mixedpolyester is a solid resin which melts at 60-65 C. and has the hydroxylnumber 58.8 and the acid number 0.5.

EXAMPLE 3 A mixture of 1 kg. (1 mole) of an adipic acid-neopentylglycolpolyester with the g. (number 106 (=3.22 percent by weight OH) and 95 g.(0.45 mole) diphenyl carbonate is treated under the conditions describedin example 1. There are obtained 90 g. (calculated g.) phenol. Theremaining mixed polyester is a viscous oil with the hydroxyl number 54and the acid number 0.3.

Yield 990 g.

EXAMPLE 4 A mixture of 3040 g. (8.3 moles) of a polyester prepared from5 moles maleic acid anhydride, 5 moles phthalic acid anhydride and 20moles neopentylglycol and having the hydroxyl number 307 (=9.3 percentby weight Ol-l), the acid number 0.3 and molecular weight 365, and of1450 (6.8 moles) diphenyl carbonate is treated under the conditionsdescribed in example i. There are obtained 1.3 kg. (calculated 1.28 kg.)

phenol. The remaining mixed polyester is a transparent yellow-coloredsolid resin with the hydroxyl number 51.5. Yield 3.19 kg.

The mixed polyester dissolves in styrene. When 2 percent by weightbenzoyl peroxide are added to a 70 percent solution of the polyester instyrene, the solution polymerizes at 100 C. to form a hard syntheticmaterial.

EXAMPLE 5 EXAMPLE 6 A mixture of 338 g. (1 mole) terephthalicacid-bis-neopentylglycol ester, 1.316 kg. (11.05 moles) 1,6-hexane-diol,and 2.350 kg. (11 moles) diphenyl carbonate is treated in the mannerdescribed in example 1, whereby 2.072 kg. (calculated 2.06 kg.) phenolare distilled off. The remaining mixed polyester is a viscous oil withthe hydroxyl number 58.8 and the acid number 0.5.

Yield 1839 g.

EXAMPLE 7 A mixture of 477 g. 1.5 moles) of an adipicacid-neopentylglycol polyester with the hydroxyl number 350, 1,316 kg.(11.15 moles) 1,6-hexane-diol and 2.450 kg. (11.5 moles) diphenylcarbonate is treated in the manner described in example 1, whereby 2.2kg. (calculated 2.16 kg.) phenol are distilled off. The remaining mixedpolyester is a waxlike product of softening point 34-35 C. with thehydroxyl number 58 and the acid number 0.

Yield 2 kg.

1 claim:

1. Process for the production of neopentylglycol-carboxylicacid-carbonic acid mixed esters which comprises transesterifying adiaryl carbonate with a neopentylglycol-carboxylic acid semiester in thetemperature range from about to about 220 C., the corresponding phenolbeing distilled off.

2. Process according to claim 1, wherein neopentylglycolmonocarboxylicacid semiesters are used.

3. Process according to claim 1, wherein neopentylglycoldicarboxylicacid disemiesters are used.

4. Process according to claim 1, wherein the neopentylglycol-carboxylicacid semiesters are reacted in admixture with monohydric alcohols.

5. Process according to claim 1, wherein the neopentylglycol-carboxylicacid semiesters are reacted in admixture with glycols having at leastfive chain members.

2. Process according to claim 1, wherein neopentylglycol-monocarboxylicacid semiesters are used.
 3. Process according to claim 1, whereinneopentylglycol-dicarboxylic acid disemiesters are used.
 4. Processaccording to claim 1, wherein the neopentylglycol-carboxylic acidsemiesters are reacted in admixture with monohydric alcohols.
 5. Processaccording to claim 1, wherein the neopentylglycol-carboxylic acidsemiesters are reacted in admixture with glycols having at least fivechain members.